I just picked up a Gamecube game called Amazing Island. I didn't have high hopes, but rentals are pretty cheap so I gave it a shot.
Anyway, I got pleasantly surprised by the creature editor it contained. Impossible to play it without thinking of Spore. The first time you make a creature it does most of it for you, but you unlock more and more stuff as you play. Basically, you pick a skeleton, then draw the body onto the skeleton similar to how I think Magic Pengel works, add in accessories such as eyes, beaks, wings, wherever you want, pick from preset coloring and patterns , pick a voice and boom you have a creature. The gameplay isn't terribly compelling, though. Basically you just take your creature through a bunch of Mario Party-style minigames. Some of the mini-games were pretty interesting. Reminds me a little of Wario Ware and Mario Party, where the challenge at first is just to see what you're supposed to do.
Making the creature is the really fun part. I think it has some kind of multiplayer too, which I'll try out tonight.
I'd definitely say it's worth renting for anybody interested in the evolution portion of Spore. I plan to play it quite a bit until it's due back Friday
